The enthalpy of combustion of carbon to carbon dioxide is -394 kJ according to the equation: C (s) + O2 (g) --> CO2 (g) How many kJ of heat are released when 24.0 g of carbon are burned in an excess of oxygen
394 kJ heat released by burning 12 g C; therefore, burning 24 g will release
394 x (24/12) = ?? kJ.
Ah, the enthalpy of combustion, how thrilling! Alright, let's calculate the amount of heat released when 24.0 grams of carbon are burned. So, first things first, we need to convert those grams to moles.
The molar mass of carbon (C) is approximately 12.01 g/mol. Therefore, 24.0 g of carbon is equal to 24.0 g divided by 12.01 g/mol, which gives us approximately 1.999 moles of carbon.
Now, since the equation states that the enthalpy change for the combustion of 1 mole of carbon is -394 kJ, we can just multiply this value by the number of moles we have.
1.999 moles * -394 kJ/mole = approximately -787.206 kJ.
So, when 24.0 g of carbon are burned, approximately -787.206 kJ of heat are released. And by the way, by "released," I don't mean it'll fly out of the fire like a mini firework show. It's just a transfer of energy, without any confetti or streamers involved.
To calculate the heat released when 24.0 g of carbon are burned in an excess of oxygen, we need to use the equation and the enthalpy of combustion.
1. Determine the moles of carbon burned:
To do this, we need to use the molar mass of carbon (C), which is 12.01 g/mol.
Moles of carbon = mass of carbon / molar mass of carbon
Moles of carbon = 24.0 g / 12.01 g/mol = 1.999 moles (approximated to 2 moles)
2. Use the balanced chemical equation to find the moles of CO2 produced:
According to the equation:
1 mole of carbon (C) produces 1 mole of carbon dioxide (CO2)
So, 2 moles of carbon (C) will produce 2 moles of carbon dioxide (CO2)
3. Calculate the heat released using the enthalpy of combustion:
The enthalpy of combustion of carbon is given as -394 kJ. This value corresponds to the combustion of 1 mole of carbon.
Hence, 2 moles of carbon will release 2 times the enthalpy of combustion.
Heat released = -394 kJ/mol * 2 mol = -788 kJ
Therefore, when 24.0 g of carbon are burned in an excess of oxygen, the heat released is -788 kJ.
To find the amount of heat released when 24.0 g of carbon are burned, we need to use the given enthalpy of combustion (-394 kJ) and the molar mass of carbon.
Here's how you can calculate it step by step:
1. Find the molar mass of carbon (C). The molar mass of carbon is approximately 12.01 g/mol.
2. Convert the mass of carbon (24.0 g) to moles. To do this, divide the mass by the molar mass:
moles of carbon = mass of carbon / molar mass = 24.0 g / 12.01 g/mol
3. Since the stoichiometric coefficient for carbon in the balanced equation is 1, the moles of carbon will be equal to the moles of carbon dioxide produced.
4. Use the stoichiometry of the balanced equation to determine the amount of heat released. The stoichiometric coefficient of carbon in the balanced equation is 1, and the enthalpy change for the combustion of carbon is given as -394 kJ:
heat released = moles of carbon x enthalpy change
= moles of carbon x -394 kJ
Now, let's plug the values into the equation:
moles of carbon = 24.0 g / 12.01 g/mol ≈ 1.998
heat released = 1.998 x -394 kJ
Therefore, approximately -786 kJ of heat will be released when 24.0 g of carbon are burned in an excess of oxygen. The negative sign indicates that the reaction is exothermic, meaning heat is released.